Nanotechnology is the big thing these days, but as with everything else there are pros and cons to the development of new technology.
Juan Pablo Pardo-Guerra of the National University of Mexico says, "Nanotechnology does have a lot of potential benefits, especially in terms of preventing chemical and biological attacks with more effective sensors."
He also says that, "nanotechnological innovations such as self-replicating nanorobots," are theoretical at best right now, but I'd be very curious to see if we will see "self-replicating robot viruses" in our lifetime. Terminator anyone?